(1) Field of the Invention
This invention relates to a novel tobacco composition and to the process for the treatment of smoking tobacco for cigars, cigarettes and/or tobacco or pipes and to other smoking products made with tobacco.
(2) Description of the Prior Art
It has long been known that a large number of products of combination found in tobacco smoke are toxic. Included among these undesirable tobacco smoke components are polycyclic aromatic compounds and their heterocyclic analogs. The highly carcinogenic effect of some polycyclic aromatic hydrocarbons is well-documented. (Smoking and Health, Report of the Advisory Committee to the Surgeon General, U.S. Public Health Publication No. 1103, Ch. 9, p. 142-146 (1963)) A specific polycyclic aromatic compound which merits special attention is benzo(a)pyrene (occurs as 1,2-benzopyrene; also referred to as 3,4-benzpyrene and benzo(e)pyrene and 4,5-benzopyrene), since it is generally present in proportionately higher quantities and has long been known to be a potent carcinogenic agent.
In an effort to lower the polycyclic aromatic hydrocarbon content of tobacco smoke, a host of various treatments of tobacco materials have been proposed in the art. For example, the addition of nitrates and nitrites to tobacco has been previously described in patents and in published literature. For example, French Patent No. 1,180,320 teaches the addition of nitrites to tobacco and cigarette paper to reduce the polycyclic aromatic hydrocarbon yield. U.S. Pat. No. 3,121,433 describes the addition of potassium nitrate to reconstituted tobacco sheet to improve its burning characteristics. U.S. Pat. No. 3,180,458 teaches the addition of potassium and sodium nitrate to tobacco and it discloses a reduction of cigarette tar yield which is caused by the increased burn rate of the cigarette. Huntley and Bergun (Analyst, volume 85, p. 727-730 (1960)) describe the addition of copper and potassium nitrates to reduce the yield of 3,4-benzopyrene from the cigarette smoke.
The treatment of tobacco compositions with platinum group metals such as platinum, palladium, rhodium, osmium, iridium or ruthenium to lower the concentration of active carcinogens such as benzopyrene in tobacco smoke is disclosed in British Patent No. 841,074.
Another approach suggested to reduce polycyclic aromatic compounds involves the use of zeolite molecular sieve compositions. For example, U.S. Pat. No. 3,292,636 discloses tobacco preparations in combination with crystalline zeolite molecular sieves such as L, X, Y, or synthetic mordanite types or naturally occuring fraujasite materials, which sieves may contain any metal containing a vapor pressure below one atmosphere at 1000.degree. C. and possessing catalytic activity for organic conversion. U.S. Pat. No. 3,572,348 also relates to a smoking preparation comprised of a zeolite material which effects a decrease in the amount of polycyclic aromatic compounds produced from the combustion of tobacco. This zeolite material is of the Y-type structure and is at least partially exchanged with zinc ion or containing metalic palladium or at least partially exchanged with zinc ions and containing metallic palladium, or is partially polyvalent zinc cation exchanged and partially decatonized and contains metallic palladium. U.S. Pat. No. 3,703,901 also discloses a Y-type zeolite structure at least partially exchanged with zinc ions and containing platinum or silver for reducing the amount of polycyclic aromatic compounds in tobacco smoke.
The use of cerium sulfate together with compounds of titanium, zirconium and tin to remove nicotine from tobacco smoke has been proposed in German Patent No. 640,193.
As indicated by the above prior art, a concerted effort has been expended to reduce deliterious substances in tobacco smoke. However, these treatments suffer various shortcomings and have not had a degree of commercial success. Therefore, any method or improvement for decreasing substantial amounts of polynuclear aromatic hydrocarbons especially benzo(a) pyrene in tobacco, which would produce a commercially feasible product, would appear to be highly desirable and beneficial. Ideally a method which can be applied or used in a continuous process compatible with existing manufacturing techniques thereby adding no appreciable cost to the production expense of the tobacco product is most desirable. Furthermore, the novel tobacco product produced therefrom should not adversely affect the taste or aroma of the tobacco smoke. The present invention fulfills all these aforementioned goals.